The present invention relates to the bridge of molded eyeglasses. The invention is particularly useful for eyeglasses of the "Oxford" or pince-nez type, although the invention need not be limited to those type of eyeglasses.
Oxford eyeglasses or pince-nez have been used for many years. Many different types of eyeglasses are kept in place by the spring action, e.g. the springiness of the material of the bridge that extends between the two lenses, which pushes the lenses toward each other and squeezes them on the nose. This pressure keeps the eyeglasses in place.
Many patents disclose different eyeglasses of this type, for instance, U.S. Patent Nos. 365,496, 1,116,153, 1,214,184, 1,654,996, 1,663,053, 1,682,038, 1,800,266, 1,873,338, 1,953,995, 1,935,224, 1,973,126, 1,973,587, 1,974,455, 2,014,092, 2,016,685, 2,064,411 and 2,071,058.
The use of Oxford eyeglasses has been largely discontinued. Eyeglasses normally employed today rely on temples and earpieces for positioning the lenses. Modern eyeglasses do not present the drawbacks of prior Oxford glasses in that they are not heavy on the nose, are more stable and do not apply a pressure on the nose which may be irritating.
Recently, there has been consumer demand for eyeglasses which can be inexpensive, can be considered disposable, and which may be purchased essentially off-the-shelf at a low price. Normal eyeglasses with temples and earpieces are available on the market with different standard sight corrections, so that a suitable pair of eyeglasses can be obtained for use and can then be disposed of. Also, disposable sunglasses are becoming available.
For normal eyeglasses and also for Oxford type eyeglasses, various techniques are known for attaching the bridge to the lens. These include attaching the ends of the bridge to frames or rims surrounding the two lenses or where the lens are unframed (at least in the region of the bridge), attaching the ends of the frame directly to the lens, e.g. by clipping them onto the lens or into grooves formed in the lens. See for example, U.S. Pat. Nos. 233,681; 235,930; 205,860; 1,227,620; 2,117,139; 2,225,038; 2,629,037; and see 3,930,824.
These bridge attachment techniques require appropriate fastening fixtures be supplied on the bridge and/or the lenses and require the separate step of applying the previously formed bridge to the previously formed lenses. Avoidance of the need for these separate fixtures and steps could decrease the expense of eyeglass production.
Various materials are used for eyeglass bridges, including various metals and plastics. Size, weight, expenses of materials and of manufacture, appearance, consistency with the lens frames are some criteria for selection of a bridge material. The simpler is the bridge design and the less that the bridge need be shaped or bent, the easier and less expensive can be production of the bridge and of the eyeglasses.